This invention relates broadly to a fastening device for securing objects to metal channels or studs, and more particularly to a sheetmetal fastener or clip for securing an electrical box to a metal stud.
In new construction, electrical junction boxes have traditionally been secured to wall framing (usually to wooden studs) before the wall is plastered or before the drywall or wallboard is fastened in place. The known means by which electrical boxes are fastened to wooden studs usually involve either the use of nails or the use of nail-like projections formed integrally with the electrical boxes, box brackets or box hangers.
Metal studs begin gaining prominence in the construction industry after World War II. Originally they were used largely for room partitioning. Their use expanded as the cost of metal studs became competitive with those of wood. Unfortunately, the use of a sheetmetal stud in place of a wooden stud prevents the use of nails or nail-like fasteners.
At this time there are a number of patented and unpatented clips or fasteners commercially available for the purpose of attaching electrical boxes to metal studs. Usually they attach to the metal stud by gripping it under pressure supplied by their own spring-temper steel appendages. However, some cannot be universally used on all electrical boxes or on all sizes of metal studs. Other are flimsy, while yet others are difficult to install.
It is thus an object of this invention to provide an improved fastener or clip for attaching electrical boxes or the like to metal studs that is affixable universally to essentially all sheetmetal boxes as well as to any standard size metal stud. Another object is to provide the clip or fastener with means that securely holds the electrical box to the metal stud so as to prevent slipping or cocking of the electrical box once installed onto a metal stud.
In providing these desirable characteristics, the improved fastener of this enclosure includes a first portion with a pair of widely spaced fingers or appendages that hook over the lip on the outermost edge of one of the stud flanges. A third appendage braces itself both on the inner surface of that stud flange and simultaneously pushes against the flange lip to cause the pair of widely spaced fingers to securely dig into the flange. Several locking stops are provided on this third appendage so that it will attach properly to studs with different width lips. Another portion of the fastener mounts to the electrical box by snugly slipping over and biting into an exposed edge on one of its sidewalls. Thus, proper electrical ground continuity is maintained between electrical box and metal stud.